A large portion of carpets used in residences are known as pile carpets formed by tufting pile yarn into a primary backing material. The yarns tufted into the primary backing form the fibrous face of the carpet. The tufted loops can optionally be cut or sheared to form tufts of a desired, constant vertical height.
Two general categories of tufted carpets are (1) a textured style, in which the tufts and the individual filaments or staples have varying degrees of crimp or curl; and (2) a straight-set style, in which the filaments or staples at the tuft tip are straight and substantially perpendicular to the plane of the carpet face. Addressing the first category of carpets, yarn that is used as pile in textured style carpets is prepared by cabling together a plurality of single yarns and setting them in their twisted condition. A texturing apparatus can be any convenient or desirable texturing device such as a texturing gear and/or or stuffer box that imparts a texture in the yarn. For example, a yarn strand exiting a drawing apparatus or a creel can be fed through texturing wheels and/or gears of a twin roll box to impart a texture into the yarn.
The yarn can also be fed into the stuffer box, within which the yarn is allowed to selectively pile up, thereby forming a yarn plug. As is typical of known texturing apparatuses, the movement of yarn into the stuffer box causes the yarn to collide initially with an end wall, and subsequently with itself, thus forming additional bends and similar shapes, called crimps, in the yarn strand as it resides therein the stuffer box. Because the yarn can be exposed to heated air, the yarn is softened. As a result, the formed crimp can be substantially permanently set therein the yarn strand as the yarn strand is subsequently cooled.
The step of texturing the yarns with the stuffer box, however, creates some issues that do not exist when producing the straight-style carpet. One such recurring problem, for example, is locating the yarn plug in a desired position in the stuffer box, because if the yarn plug is positioned in a desired location within the stuffer box, yarn texture consistency can be improved. For example, it can be desirable for yarn to form a yarn plug at only the front or alternatively the rear of the stuffer box. Thus, there is a need in the art for a device for monitoring, improving and/or controlling the position of the yarn plug within the stuffer box.
Yarn is typically fed to the texturing apparatus with at least one pre-feed roller. The at least one pre-feed roller is a driven roll around which the yarn can wrap. However, if the speed of the at least one pre-feed roller varies, tension in the yarn being fed to the texturing apparatus can change, and the yarn crimped by the texturing apparatus can vary. When this yarn is woven or tufted into a finished product, such as, for example and without limitation, carpet, the variations in the yarn can be readily apparent. Furthermore, other manufacturing variations can create variations in the consistent, controlled formation of the texture in the yarn. For example, variations in the process temperature or pressure can reduce the consistency of the yarn being produced which will become apparent when the yarn is woven or tufted into a finished product. Thus, there is a need in the art for monitoring, improving and/or controlling the formation of a texture in the yarn.